Forces from Ethiopia's rebel Tigray region fired rockets on Friday at the distant capital of the neighbouring Amhara region, Amhara authorities said, raising worries the conflict could spill into a wider war.

Hundreds, perhaps thousands, of people have been killed and tens of thousands of refugees have fled from two weeks of fighting in Tigray, raising questions of whether Prime Minister Abiy Ahmed can hold his ethnically diverse nation together.

"The illegal TPLF group have launched a rocket attack around 1:40 a.m. in Bahir Dar," the Amhara government's communications office said on its Facebook page, referring to the Tigray People's Liberation Front. It said the rockets caused no damage.

Bahir Dar, the lakeside Amhara regional capital, is located hundreds of miles from the fighting in Tigray. Tigrayan refugees have told Reuters the Amhara militia is fighting on the government side, and the two regions have a border dispute.

A local journalist and another resident in Bahir Dar both told Reuters they had heard two explosions and had been told by people in the area that at least one of the missiles landed near the airport.

Ethiopia, a federation of 10 ethnic regions, was dominated for decades by Tigrayans in a TPLF-led ruling coalition, until Abiy, who is of Amhara and Oromo descent, took power two years ago. He says he aims to share authority more fairly in the country; the TPLF accuses him of pursuing a vendetta against former officials and restricting regional rights.

The conflict erupted two weeks ago after what the government called a TPLF attack on army forces stationed in the region.

A week ago, Tigray forces fired rockets at two airports in Amhara. They have also fired at rockets into the neighbouring nation of Eritrea, which has a long-running enmity with the TPLF leadership and made peace with Ethiopia in 2018, earning Abiy the Nobel Peace Prize.

Reports of ethnically motivated killings have emerged during the conflict. Rights group Amnesty International documented a mass killing of civilians, many of whom appeared to be Amhara, by what it says were Tigrayan forces on Nov. 9-10, which the Tigray authorities denied. Refugees fleeing the conflict into Sudan have said they were targeted for being Tigrayan.

Tigray forces accused the government of bombing a university in the Tigray capital of Mekelle on Thursday. There was no immediate response from the government, although officials have said they are only attacking military targets.

It has been impossible to verify assertions on all sides because telephone lines and internet links to Tigray have been severed since the conflict began.

On Thursday, Ethiopia said it was closing in on Mekelle, which the rebels have said they are fighting to defend.

Since taking power, Abiy has freed political prisoners and loosened what was once one of the most repressive political and economic systems in Africa. But the new freedoms have also been accompanied by bouts of violence as regional bosses vie with each other and the government for power, money and land.

Mountainous Tigray accounts for only about 5% of the population, but has a long history of dominating the security services. Tigrayans are proud of a long history of guerrilla warfare, having spearheaded a conflict that toppled a Communist regime in 1991.